I am getting 3-4 mil per attack hitting cold wars. Not even maxed loot, 600k or so of each plus 5-6k oil and loot bonus. That works out to 25-33 attacks to finish this event, which is much easier than most of the recent ones.
Attacking in lower leagues or targetting ages below you will take more attacks, but presumably you lose fewer resources on each attack and can do more of them.
Plus, it doesn't matter whether you have storage space for the loot, you get credit regardless. All in all, this will be the first one I expect to finish completely in the last few months.